The present invention relates to an image forming apparatus such as a copying machine, a laser beam printer, a facsimile or the like.
Conventionally, there has been proposed, as an example of the image forming apparatus above-mentioned, a clamshell-type image forming apparatus having the main body divided into two units, i.e., an upper unit and a lower unit, which are disposed such that a paper delivery passage is formed therebetween and in which the upper unit is rotatably and openably connected to the lower unit.
In this clamshell-type image forming apparatus, the upper unit is normally biased in the opening direction by a biasing member such as a spring or the like. Accordingly, when the upper unit is opened, the upper unit is prevented from being downwardly rotated. Further, a rotatably openable front cover is disposed at the fronts of the upper and lower units for facilitating a jam processing or maintenance. To maintain the upper unit as closed, the upper unit has a hook to be engaged with an engagement member disposed at the lower unit. Generally, this hook is rotatable around an axis parallel to the axis of rotation of the upper unit.
According to the arrangement above-mentioned, when the image forming apparatus is vibrated in the course of transportation or the like, the hook may be rotated and disengaged from the engagement member of the lower unit. If the hook is disengaged from the engagement member of the lower unit, this disadvantageously causes the upper unit to be unexpectedly opened since the upper unit is biased in the opening direction by the biasing member. Accordingly, side plates forming portions of the frames of the upper and lower units are connected to each other with bolts or the like, or there is additionally disposed a whirl-stop member for preventing the hook from being rotated, thus preventing the upper unit from being unexpectedly opened.
In a small copying machine particularly for a domestic use, however, the user may fail to take out such bolts or whirl-stop member although the bolts or whirl-stop member should be taken out. In such a case, even though the user wants to open the upper unit at the time of a jam processing or the like, the upper unit cannot be opened. Accordingly, the user may misunderstand the situation and think that the copying machine is out of order.
After being taken out from the image forming apparatus, such bolts or whirl-stop member are generally thrown away. Accordingly, when moving the image forming apparatus once installed at a predetermined place, to another place, it is not possible to prevent the upper unit from being unexpectedly opened due to vibration.